I can't stand clowns-evil creepy beings that they are. I've had nightmares about them (the last one was about six months ago), and I saw IT.
I think the main issue is the fact that they have their true identity covered with big smiles and lots of makeup, which makes them really really creepy.
A couple years ago a clown was hired for an event at work and a couple people had to leave because they were freaking out. I wasn't that bad, well, okay to be honest I was kinda rooted in my spot like a potted plant until the clown passed then I just avoided them until they left... but in the end I survived to tell the tale.